If you use Adobe Lightroom, either the current version (2.x) or the Beta (3) a great resource is Victoria Bampton, the "Lightroom Queen".
She offers a ton of free resources like "what's new in Lightroom 3" and a thorough comparison between Lightroom 2 and 3 and Lightroom Keyboard Shortcuts (as a free download).
Victoria also offers a "Missing Lightroom FAQ's" series (for all versions of Lightroom) for sale in eBook form.
Se be sure to add the Lightroom Queen as one of your Lightroom resources.
